Help!

Hi it seems I have been having the same problem as most with getting the game to install - initially I did it without Steam but it crashed and when I did it with Steam it was giving me the authentication code not accepted message - i must have installed and uninstalled a hundred times! the problem now is the game is not even reading in my cd drive...every time it goes to load up nothing happens...ive tried autorunning it by rightclicking but it stil wont happen - any ideas??